ffmediafile: Add fixes for recent cflags changes

Related: #2771

modules/media/gtkffmediafile.c

@@ -171,6 +171,7 @@ G_DEFINE_TYPE_EXTENDED (GtkFfMediaFile, gtk_ff_media_file, GTK_TYPE_MEDIA_FILE,
                         G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
                                                gtk_ff_media_file_paintable_init))
 
+G_MODULE_EXPORT
 void
 g_io_module_load (GIOModule *module)
 {
@@ -186,17 +187,20 @@ g_io_module_load (GIOModule *module)
                                   0);
 }
 
+G_MODULE_EXPORT
+G_GNUC_NORETURN
 void
 g_io_module_unload (GIOModule *module)
 {
   g_assert_not_reached ();
 }
 
+G_MODULE_EXPORT
 char **
 g_io_module_query (void)
 {
   char *eps[] = {
-    GTK_MEDIA_FILE_EXTENSION_POINT_NAME,
+    (char *) GTK_MEDIA_FILE_EXTENSION_POINT_NAME,
     NULL
   };